A simple illustration compares a capacitor to a dipole ... [lcamtuf]’s animations show the action of a sine wave on a 1/4 wave dipole, bringing a nearly imaginary concept right into the real ...

Sine-wave speech can be thought of as a sort of auditory illusion, a sensory edge case in which one’s experience has a clear “before” and “after” moment, like going through a one-way door.